Where could I find the image capacity of flash cards? For example, I would be using a 256M or a 512M card at maximum resolution in a camera that has 4.1MB(3.9 effective). I realize that this is a relative amount, but I would like to get some idea. Thanks

"It depends" is the only real answer to your question - what resolution and compression are you going to use, or are you going to shoot in RAW? Taking a look at the review for the specific camera you are interested in will give the best answer, e.g., http://www.steves-digicams.com/2001_reviews/g2.html for Canon's PowerShot G2.